fischertechnik community forum

Hi all,

I came across this small robot with ft (in Spanish). The author does not show a schematic, but to me it looks like the Arduino UNO drives the two mini-motors directly, i.e. with no motor driver. My instinct says that's electrically unsafe and you shouldn't do that, but it's intriguing anyway. Any thoughts?

Thanks in advance,

Rubem

====================== Google translate

Hallo zusammen,

Ich stieß auf diesen kleinen Roboter mit ft (auf Spanisch). Der Autor zeigt keinen Schaltplan, aber für mich sieht es so aus, als ob der Arduino UNO die beiden Minimotoren direkt antreibt, d.h. ohne Motortreiber. Mein Instinkt sagt, dass das elektrisch unsicher ist und Sie das nicht tun sollten, aber es ist trotzdem interessant. Irgendwelche Gedanken?

Danke im Voraus,

Rubem

And I've been using motor drivers all along, stupid me!

Actually, he will fry his Arduino that way, the limit per pin is 40mA, let alone inrush surge.

Jan

Dt.: Nee, geht nicht, macht den Arduino kaputt.

Hi Jan,

juh hat geschrieben: ↑

23 Jan 2023, 20:31

No, it doesn't work, it breaks the Arduino.

:sigh of relief: Yes, that's what I thought.

Actually, he will fry his Arduino that way, the limit per pin is 40mA, let alone inrush surge.

That's probably the reason he didn't write the follow-up article he promised

Thanks,

Rubem

It works!
You see this shit everywhere. If you did not block the motor the ATmege (!) can do it. This small motors don't need much Amps. But never use the engine as generator.
Better is to use a driver like the L293 or better

bücherwurm hat geschrieben: ↑

24 Jan 2023, 09:35

It works!

Are you ready to show proof of that?

One can do it but one does not have to.
https://starthardware.org/motorsteuerun ... r-arduino/
I would always put at least a transistor between the Arduino and Motor:
https://starthardware.org/motorsteuerun ... ransistor/

We need to define "it".

I am talking about the ft mini motor (edit: in the model from the initial link), mine are drawing ca. 100mA when running without any load. And we are talking about no protection at all, not even a diode that the first example uses.

Dt.: Worum geht es? Um ft Mini-Motoren direkt am IO-pin ohne jeden Schutz.

At 9V the small black ft motor takes 20mA and at 5V only 16mA - my version => no problem (disregarding all other problems)

The XS actually only draws ca. 20mA without load, I mistook my measurements of the older, wider Mini Motor. Apart from that, I'll be happy to see the model shown in rubem's post "working", particularly when runs into an obstacle.

Hallo...
For all who want to build that shit - dont do that.
If the motor was only wit a litle load, the UNO Output is broke down.
Please use, may be a BD Transistor or someting like that, to run a ft-Motor.
--
Für alle die meinen den Schrott nachzubauen - macht es NICHT.
Wenn der Motor nur minimal belastet wird, geht der Ausgang (oder mehr) in die ewigen elektronischen Jagdgründe, raucht ab, schmökelt vor sich hin...
Bitte mindestens einen Leistungstransistor wie die alten BD Transistoren oder was in der Art nehmen, um einen ft-Motor anzutreiben.

Mit freundlichen Grüßen
fishfriend
Holger Howey